Weifang Audi A6 1.8MT manual boring, why not do it?

Look at the maintenance cycle, clean the oil circuit and throttle, and change the three filters and three oils.

If all the above are done, see if there is any problem with the recent oil quality and try to refuel somewhere else.

The main problem of weakness is low efficiency and poor exhaust recently (not smooth, but a little back pressure is normal)

Excessive carbon deposition in the cylinder will reduce the ignition efficiency of the spark plug, which will affect the power output.